diff --git a/mlir/include/mlir/Dialect/Complex/IR/CMakeLists.txt b/mlir/include/mlir/Dialect/Complex/IR/CMakeLists.txt
--- a/mlir/include/mlir/Dialect/Complex/IR/CMakeLists.txt
+++ b/mlir/include/mlir/Dialect/Complex/IR/CMakeLists.txt
@@ -1,2 +1,7 @@
 add_mlir_dialect(ComplexOps complex)
 add_mlir_doc(ComplexOps ComplexOps Dialects/ -gen-dialect-doc)
+
+set(LLVM_TARGET_DEFINITIONS ComplexAttributes.td)
+mlir_tablegen(ComplexAttributes.h.inc -gen-attrdef-decls)
+mlir_tablegen(ComplexAttributes.cpp.inc -gen-attrdef-defs)
+add_public_tablegen_target(MLIRComplexAttributesIncGen)
diff --git a/mlir/include/mlir/Dialect/Complex/IR/Complex.h b/mlir/include/mlir/Dialect/Complex/IR/Complex.h
--- a/mlir/include/mlir/Dialect/Complex/IR/Complex.h
+++ b/mlir/include/mlir/Dialect/Complex/IR/Complex.h
@@ -27,4 +27,7 @@
 #define GET_OP_CLASSES
 #include "mlir/Dialect/Complex/IR/ComplexOps.h.inc"
 
+#define GET_ATTRDEF_CLASSES
+#include "mlir/Dialect/Complex/IR/ComplexAttributes.h.inc"
+
 #endif // MLIR_DIALECT_COMPLEX_IR_COMPLEX_H_
diff --git a/mlir/include/mlir/Dialect/Complex/IR/ComplexAttributes.td b/mlir/include/mlir/Dialect/Complex/IR/ComplexAttributes.td
new file mode 100644
--- /dev/null
+++ b/mlir/include/mlir/Dialect/Complex/IR/ComplexAttributes.td
@@ -0,0 +1,43 @@
+//===- ComplexAttributes.td - Definitions for complex attributes -*- tablegen -*-=//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef COMPLEX_ATTRIBUTE
+#define COMPLEX_ATTRIBUTE
+
+include "mlir/IR/AttrTypeBase.td"
+include "mlir/Dialect/Complex/IR/ComplexBase.td"
+
+//===----------------------------------------------------------------------===//
+// Complex Attributes.
+//===----------------------------------------------------------------------===//
+
+class Complex_Attr<string attrName, string attrMnemonic>
+    : AttrDef<Complex_Dialect, attrName> {
+  let mnemonic = attrMnemonic;
+}
+
+def Complex_NumberAttr : Complex_Attr<"Number", "number"> {
+  let summary = "A complex number attribute";
+
+  let description = [{
+    A complex number attribute.
+
+    Example:
+
+    ```mlir
+    #complex.number<:f64 1.0, 2.0>
+    ```
+  }];
+
+  let parameters = (ins APFloatParameter<"">:$real, APFloatParameter<"">:$imag, AttributeSelfTypeParameter<"">:$type);
+
+  let genVerifyDecl = 1;
+  let hasCustomAssemblyFormat = 1;
+}
+
+#endif // COMPLEX_ATTRIBUTE
diff --git a/mlir/include/mlir/Dialect/Complex/IR/ComplexBase.td b/mlir/include/mlir/Dialect/Complex/IR/ComplexBase.td
--- a/mlir/include/mlir/Dialect/Complex/IR/ComplexBase.td
+++ b/mlir/include/mlir/Dialect/Complex/IR/ComplexBase.td
@@ -22,6 +22,7 @@
   let dependentDialects = ["arith::ArithmeticDialect"];
   let hasConstantMaterializer = 1;
   let emitAccessorPrefix = kEmitAccessorPrefix_Prefixed;
+  let useDefaultAttributePrinterParser = 1;
 }
 
 #endif // COMPLEX_BASE
diff --git a/mlir/lib/Dialect/Complex/IR/CMakeLists.txt b/mlir/lib/Dialect/Complex/IR/CMakeLists.txt
--- a/mlir/lib/Dialect/Complex/IR/CMakeLists.txt
+++ b/mlir/lib/Dialect/Complex/IR/CMakeLists.txt
@@ -7,6 +7,7 @@
 
   DEPENDS
   MLIRComplexOpsIncGen
+  MLIRComplexAttributesIncGen
 
   LINK_LIBS PUBLIC
   MLIRArithmeticDialect
diff --git a/mlir/lib/Dialect/Complex/IR/ComplexDialect.cpp b/mlir/lib/Dialect/Complex/IR/ComplexDialect.cpp
--- a/mlir/lib/Dialect/Complex/IR/ComplexDialect.cpp
+++ b/mlir/lib/Dialect/Complex/IR/ComplexDialect.cpp
@@ -8,6 +8,10 @@
 
 #include "mlir/Dialect/Arithmetic/IR/Arithmetic.h"
 #include "mlir/Dialect/Complex/IR/Complex.h"
+#include "mlir/IR/Builders.h"
+#include "mlir/IR/DialectImplementation.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/TypeSwitch.h"
 
 using namespace mlir;
 
@@ -18,6 +22,10 @@
 #define GET_OP_LIST
 #include "mlir/Dialect/Complex/IR/ComplexOps.cpp.inc"
       >();
+  addAttributes<
+#define GET_ATTRDEF_LIST
+#include "mlir/Dialect/Complex/IR/ComplexAttributes.cpp.inc"
+      >();
 }
 
 Operation *complex::ComplexDialect::materializeConstant(OpBuilder &builder,
@@ -32,3 +40,71 @@
     return builder.create<arith::ConstantOp>(loc, type, value);
   return nullptr;
 }
+
+#define GET_ATTRDEF_CLASSES
+#include "mlir/Dialect/Complex/IR/ComplexAttributes.cpp.inc"
+
+LogicalResult complex::NumberAttr::verify(
+    ::llvm::function_ref<::mlir::InFlightDiagnostic()> emitError,
+    ::llvm::APFloat real, ::llvm::APFloat imag, ::mlir::Type type) {
+
+  if (!type.isa<FloatType>())
+    return emitError()
+           << "element of the complex attribute must be float like type.";
+
+  const auto &typeFloatSemantics = type.cast<FloatType>().getFloatSemantics();
+  if (&real.getSemantics() != &typeFloatSemantics)
+    return emitError()
+           << "type doesn't match the type implied by its `real` value";
+  if (&imag.getSemantics() != &typeFloatSemantics)
+    return emitError()
+           << "type doesn't match the type implied by its `imag` value";
+
+  return success();
+}
+
+void complex::NumberAttr::print(AsmPrinter &printer) const {
+  printer << "<:";
+  printer.printType(getType());
+  printer << " ";
+  printer.printFloat(getReal());
+  printer << ", ";
+  printer.printFloat(getImag());
+  printer << ">";
+}
+
+Attribute complex::NumberAttr::parse(AsmParser &parser, Type odsType) {
+  if (failed(parser.parseLess()))
+    return {};
+
+  if (failed(parser.parseColon()))
+    return {};
+
+  Type type;
+  if (failed(parser.parseType(type)))
+    return {};
+
+  double real;
+  if (failed(parser.parseFloat(real)))
+    return {};
+
+  if (failed(parser.parseComma()))
+    return {};
+
+  double imag;
+  if (failed(parser.parseFloat(imag)))
+    return {};
+
+  if (failed(parser.parseGreater()))
+    return {};
+
+  bool unused = false;
+  auto realFloat = APFloat(real);
+  realFloat.convert(type.cast<FloatType>().getFloatSemantics(),
+                    APFloat::rmNearestTiesToEven, &unused);
+  auto imagFloat = APFloat(imag);
+  imagFloat.convert(type.cast<FloatType>().getFloatSemantics(),
+                    APFloat::rmNearestTiesToEven, &unused);
+
+  return NumberAttr::get(parser.getContext(), realFloat, imagFloat, type);
+}
diff --git a/mlir/test/Dialect/Complex/attribute.mlir b/mlir/test/Dialect/Complex/attribute.mlir
new file mode 100644
--- /dev/null
+++ b/mlir/test/Dialect/Complex/attribute.mlir
@@ -0,0 +1,19 @@
+// RUN: mlir-opt %s -split-input-file -allow-unregistered-dialect -verify-diagnostics | FileCheck %s
+
+func.func @number_attr_f64() {
+  "test.number_attr"() {
+    // CHECK: attr = #complex.number<:f64 1.000000e+00, 0.000000e+00> : f64
+    attr = #complex.number<:f64 1.0, 0.0>
+  } : () -> ()
+
+  return
+}
+
+func.func @number_attr_f32() {
+  "test.number_attr"() {
+    // CHECK: attr = #complex.number<:f32 1.000000e+00, 0.000000e+00> : f32
+    attr = #complex.number<:f32 1.0, 0.0>
+  } : () -> ()
+
+  return
+}